In this experiment we impose a reduction of the THC consistent with earlier experiments with the Hadley Centre coupled model and study the atmospheric response. The current phase of the project uses the Hadley Centre atmospheric model in conjunction with a simplified thermodynamic ("slab" ocean) which comprises a single layer ocean with prescribed heat and salinity transports. We impose surface fields which reflect the fully-coupled model's response to an imposed THC slowdown. The experiment is thus consistent with previous coupled model work with the same model at the same resolution. The essence of our THC experiment is to look at how the atmosphere would respond to such changes in the ocean, given a THC slowdown.

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Accounting for model uncertainty in climate prediction is still in its infancy, but recent years have seen considerable progress with the development of the first “perturbed physics” ensemble forecasting systems for the analysis of the response to anthropogenic (CO2) forcing. This project will be the first to extend the perturbed-physics ensemble methodology to study the role of the hydrological cycle in possible rapid climate change.

See here for a discussion of how distributed computing works. Climateprediction.net has over 50,000 participants as of today. Unfortunately, the software they use is only available for the Windows platform. Unix-based systems (like MacOS X) and Unix-like systems (like Linux), which tend to run these sorts of apps particularly well, can't participate. Hopefully someone will put together a distributed climate simulation using BOINC!

Well, until they have a Mac client, at least I won't have to choose between this and SETI@home.